Air lift



Nov. 1, 1966 2 F REPP 3,282,226

' AIR LIFT Filed June 29, 1964 I; I H4 Hi pg I" 44 n? N Frd c]. Repp 34 INVENTOR.

BY M /M 3421 flffys.

United States Patent 3,282,226 AIR LIFT Fred .1. Repp, Portland, Oreg., assignor to Cornell Manufacturing (10., Portland, 0reg., a corporation of Oregon Filed June 29, 1964, Ser. No. 378,745 Claims. (Cl. 103-232) This invention relates to a novel form of air lift, which in fluid-handling systems may be employed to circulate a fluid in a pipe or conduit. The air lift of the invention features a construction which enables the same to be cleaned easily, and thus has particular utility in fluidhandling systems where clogging presents problems.

In the air lift contemplated, streams of air are introduced into liquid standing in a vertical reach of pipe, where the pipe extends down into a pool of such liquid and has an open bottom end through which liquid may flow into the pipe. With air introduced into the liquid within the pipe, the liquid and air mixture resulting is lighter than the liquid in the pool, and thus the weight of the liquid in the pool forces liquid up through the pipe and produces flow. While such air lifts are relatively simple and have many advantages, a drawback common to many has been that they are prone to become clogged, and after such clogging are dificult to clean.

To amplify further, an air lift operates best if there is intimate mixing of air with the liquid in the pipe, and such mixing is promoted if the passage of air int-o the pipe is by way of multiple fine streams of air. Small ports or apertures in the side wall of the pipe accommodate such air fiow, but such apertures, because of their size, and particularly if liquid mixtures containing solids are handled, render the lift susceptible to clogging. The problem becomes more acute in systems where the air lift is operated intermittently, and back flow of liquid into the apertures occurs periodically.

A general object of this invention is to provide a novel form of air lift, which features a detachable pipe section (containing apertures or other air flow means for introducing air to the liquid handled) which is easily removed to facilitate cleaning.

More specifically, the invention concerns an air lift, including a removable pipe section with means to accommodate the flow of air inwardly through the sides thereof, and means around the outside of this pipe section which ordinarily remains in place and defines a chamber for the supply of air to the periphery of the pipe section. A seal provided between this last-mentioned means and the pipe section, is broken open on removal of the pipe section for cleaning purposes.

Another object of the invention is to provide an air lift of the above description which is readily reassembled after cleaning Thus, the air lift may comprise an outer fixed part, also referred to herein as a socket, having open top and bottom ends, which receives the perforated bottom end of a removable pipe section and funnels fluid into this perforated end. Novel means around the top of the socket seals the socket to the outside of the removable pipe section, which seal is broken open by lifting the removable pipe section out of the socket. The removable pipe section may readily be dropped back into the socket to reassemble the air lift in proper operating condition.

Various other novel features and objects of the invention will become more apparent as the following description is read in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side elevation of portions of a fluid-handling system constructed according to an embodiment of the invention;

FIG. 2 is an enlarged cross sectional view, illustrating an air lift in the fluid-handling system; and

3,282,226 Patented Nov. 1, 1966 "ice FIG. 3 is a cross sectional view, taken generally along the line 3-3 in FIG. 2.

As mentioned earlier, the air lift of the invention is particularly adapted for handling fluid mixtures where clogging presents a problem. A sewage treatment plant exemplifies a specific application for the air lift, as sewage in addition to water contains large amounts of solid and semisolid material. While the invention is described in connection with such a plant, it should be understood that this is for reasons of illustration only.

Referring to FIG. 1, 10 indicates a portion of a tank in a sewage treatment plant, such tank including a bottom 12 and a wall 16 dividing the tank into two compart-' ments or chambers. A compartment 18 on the right of wall 16 comprises a settling compartment, and for the purpose of this description, it will be assumed that it is desired to transport liquid from this compartment and deposit it to the left of wall 16 in a compartment 19. Also for purposes of this description, it will be assumed that the level of liquid in compartment 18 normally is approximately at the level indicated at 20.

A sewage treatment plant of the general type described above is more fully disclosed in a copending application entitled Apparatus for Producing Gas-Liquid Mixtures, filed on the same date as this application.

Fluid is carried from compartment 18 to compartment 19 by a conduit 22, which includes a vertical pipe section 24, a horizontal pipe section 26, open at end 2611, and an elbow 28 connecting the two pipe sections. Vertical section 24 is open at the bottom end thereof, as shown in FIG. 2 at 24a.

The air lift which produces flow upwardly in vertical pipe section 24 and thence out section 26 is shown generally at 30. The air lift, it will be noted, is located well below the normal level of liquid in compartment 18, adjacent the base of pipe section 24. With air admitted by the air lift to liquid in pipe section 24, the liquid air mixture resulting above the air lift is lighter than the liquid in compartment 1-8, and the weight of the liquid in this compartment forces liquid upwardly in pipe section 24 and thence outwardly through pipe section 26 into compartment 19.

Referring now to FIGS. 1, 2, and 3, the air lift comprises what is referred to herein as an outer pipe section, shell, or socket 34 normally mounted in a fixed position adjacent the base of the tank. Thus, in FIG. 1, a bracket 36 is shown fastened to wall 18 of the tank which is also fastened to the socket and supports the socket. Socket 34 is open at opposite ends, i.e., ends 34a and 34b. Top portion 34c of the socket has a larger diameter than bottom portion 34d, and intermediate the ends of the socket a ledge 38 is formed which constitutes means extending radially inwardly on the inside of the socket forming a sea-t.

Pipe section 24 which extends into the socket has its open bottom end 24a adjacent ledge 38. Around the pipe section, and defined by the inside of the socket and the outside of the vertical pipe section is an annular chamber 40.

Integral with pipe section 24 and extending circumferentially thereabout, is a skirt 42, including around the perimeter thereof an axially extending flange 44. As shown in FIG. 2 with the parts in operative position, the flange extends downwardly over the outside of upper marginal portions of socket 34.

Secured in any suitable manner to the underside of skirt 42, and interposed between the top of the socket and the skirt, is a seal 46. The top edge of the socket may be whereby a sealed relationship exists between the skirt and the top of the socket.

Below seal 46, in that portion of the vertical pipe section that is encompassed by the socket, are a series of ports or apertures 50 extending through the wall of pipe section 24. These are distributed circumferentially about the pipe section and constitute air flow means through which air flows to the interior of the vertical pipe section from chamber 40. Connected to socket 34 is a supply pipe 54 for supplying air from a suitable source of pressurized air to supply chamber 40.

Supporting conduit means 22 including vertical pipe section 24 adjacentthe top of the tank is a notch 55 in wall 16. Pipe section 26 rests in this notch, with the sides and bottom of the notch cradling the pipe section.

The operation of the device should be obvious from the above description. Briefly explaining this operation, to produce flow into chamber 19, air under pressure is admitted to chamber 40 from the supply pipe, and such air travels as multiple streams into vertical pipe section 24 through apertures 50. Streams of air on being introduced to the liquid in the pipe section become dispersed as bubbles in this liquid, with the result that a liquid air mixture is produced having a density which is less than the density of the remaining liquid in chamber 18. As a consequence, liquid flows upwardly into conduit means 22 through the base of socket 34, and thence is discharged into chamber 19.

With intermittent operation of the air lift, and with stoppage of air flow from the supply pipe, liquid in conduit means 22 tends to flow into chamber 40 through apertures 50, and thence drain into air supply pipe 54. This backflow of liquid, particularly if such contains 7 solid matter, might well introduce clogging of apertures 50 after a period-of time. With the structure of the invention, however, such clogging is easily taken care of, as the apertures are easily cleaned without a major shutdown of the plant.

More specifically, to clean the apertures, conduit means 22 including vertical pipe section 24 is lifted up with the lower end of pipe section 24 in the process drawing out of socket 34. With lifting up of section 24, the seal existing between skirt 42 and socket 34 is broken. Conduit means 22 may then be entirely removed from the tank, to enable a workman to clean the apertures or perforations of any sediment. After such cleaning, the conduit means is repositioned merely by dropping it downwardly into the tank, with the bottom end of vertical pipe section 24 fitting within the socket.

Because of the somewhat larger diameter of the upper portion of the socket, the initial fitting of the bottom end of pipe section 24 into the socket is done relatively easily. A sealed relationship is again established between pipe section 24 and-the top of the socket when the pipe is finally lowered, when edge 48 comes into contact with seal 46. The flange around the outside of skirt 42 holds the parts in proper centered position.

With the seal attached to the underside of skirt 42, the seal may be cleaned on removal of conduit means 22, and if necessary, replaced. Thus when cleaning of either apert-ures 50 or seal 46 is performed, there is no need to empty compartment 18 of its contents, nor is there any need to use tools to disconnect fittings at the location of the air lift.

While an embodiment of the invention has been described, it is not intended to be limited specifically thereto, as various changes and variations are possible. It is intended to cover all modifications of the invention as would be apparent to one skilled in the art, and that come Within the scope of the appended claimi.

It is claimed and desired to secure by Letters Patent:

1. An air lift comprising a socket portion open at top and bottom ends,

a pipe including a bottom end, which bottom end extends downwardly into said socket portion, said bottom end being removable through said open top of said socket portion,

a skirt portion joined to the pipe extending radially of the pipe and supporting the pipe on the top of said socket portion,

a seal between the skirt and top of the socket portion urged into sealing relationship between the two by the weight of the pipe,

aperture means in the wall of the pipe connecting the inside of the pipe with the inside of said socket, and

means for supplying air to the inside of said socket portion.

2. The combination of a tank adapted to hold liquid at a level adjacent the top of the tank,

a socket portion with open top and bottom ends mounted in a fixed position inside said tank below said level,

a removable pipe including a bottom end, which bottom end extends downwardly into the tank and into said socket portion, said bottom end being removable through said open top of said socket portion,

a skirt portion joined to the pipe extending radially out from the latter and supporting the pipe on the top of said socket portion,

a seal between said skirt and top of the socket portion urged into sealing relationship between the two by the weight of the pipe and the pressure of liquid within the tank,

apertures in the wall of the pipe below said seal connecting the inside of the pipe and the inside of the socket portion, and

air-supply means for supplying air to the inside of said socket portion.

3. The air lift of claim 1, wherein said socket portion has a beveled top edge, and said skirt portion has an axially extending flange around the perimeter thereof encompassing the circumferential outer surface portions of said socket portion adjacent said beveled top edge.

4. The air lift of claim 1, wherein said seal is attached to the underside of the skirt portion, and said seal is separable from the top of the socket portion by being carried away with the skirt portion upon the bottom end of said pipe being removed through said open top of said socket portion.

5. The combination of claim 2, wherein said socket portion has a beveled top edge, said skirt portion has an axially extending flange around the perimeter thereof encompassing circumferential outer surface portions of said socket portion adjacent said beveled top edge, and said seal is attached to the underside of said skirt portion and is separated from said beveled top edge of the socket portion on removal of the bottom end of said pipe through the open top of said socket portion.

References Cited by the Examiner UNITED STATES PATENTS 562,266 6/1896 Young et al. 103-232 2,062,799 12/1936 Scott 103-232 2,144,833 1/1939 Crickmer 103-232 2,730,496 1/1956 Zavod 103232 MARTIN P. SCHWADRON, Primary Examiner.

MARK NEWMAN, Examiner. W. J. K A Assistant E aminer. 

1. AN AIR LIFT COMPRISING A SOCKET PORTION OPEN AT TOP AND BOTTOM ENDS, A PIPE INCLUDING A BOTTOM END, WHICH BOTTOM END EXTENDS DOWNWARDLY INTO SAID SOCKET PORTION, SAID BOTTOM END BEING REMOVABLE THROUGH SAID OPEN TOP OF SAID SOCKET PORTION, A SKIRT PORTION JOINED TO THE PIPE EXTENDING RADIALLY OF THE PIPE AND SUPPORTING THE PIPE ON THE TOP OF SAID SOCKET PORTION, A SEAL BETWEEN THE SKIRT AND TOP OF THE SOCKET PORTION URGED INTO SEALING RELATIONSHIP BETWEEN THE TWO BY THE WEIGHT OF THE PIPE, APERTURE MEANS IN THE WALL OF THE PIPE CONNECTING THE INSIDE OF THE PIPE WITH THE INSIDE OF SAID SOCKET, AND MEANS FOR SUPPLYING AIR TO THE INSIDE OF SAID SOCKET PORTION. 